Multiband Antenna Dual-Band Resonance Design
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Solution Overview
Problem
Conventional monopole antennas with a folding-back structure cannot effectively resonate in both the 2.4 GHz and 5 GHz frequency bands required for IEEE 802.11b/g and IEEE 802.11a wireless LAN communication, failing to provide necessary resonance frequencies for dual-band wireless LAN communication.
Innovation Solution
A multiband antenna design featuring a pole element, an L-shaped folded-back element, and an L-shaped added element, where the pole element resonates at the 2.4 GHz frequency, the folded-back element resonates at the 5 GHz frequency, and the added element adjusts resonance frequencies, allowing for dual-band operation by optimizing the lengths and connections of these elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a monopole antenna with folding-back structure is used to achieve resonance at frequency f0, then the antenna can resonate at f0 and 3f0, but the resonance frequencies cannot satisfy both 2.4 GHz and 5 GHz bands required for wireless LAN communication
Solution Approach 1:
The antenna element is divided into three distinct sections: a pole element (first section) that resonates at the first frequency (2.4 GHz), an L-shaped folded-back element (second section) that resonates at the second frequency (5 GHz), and an L-shaped added element (third section) that adjusts resonance characteristics. This segmentation allows each section to contribute differently to the overall resonance behavior, enabling dual-band operation.
Solution Approach 2:
The antenna structure transitions from a simple linear monopole configuration to a multi-dimensional structure with L-shaped folded-back and added elements. This dimensional change introduces new resonance paths and current distributions that enable resonance at both 2.4 GHz and 5 GHz frequencies simultaneously, overcoming the limitation of conventional monopole antennas.
2Manufacturing precision
If the antenna element length is adjusted to resonate at 2.45 GHz, then the first resonance frequency is correct for 2.4 GHz band, but the third resonance frequency becomes approximately 7.38 GHz instead of the required 5 GHz band
Solution Approach 1:
Different sections of the antenna element are designed with different geometries and lengths to create local resonance characteristics. The pole element has a specific length for 2.4 GHz resonance, while the L-shaped folded-back element has dimensions optimized for 5 GHz resonance. This local quality differentiation allows precise control over resonance frequencies at different locations along the antenna structure.
Solution Approach 2:
The antenna design employs multiple geometric parameters including the length of the pole element, the dimensions of the L-shaped folded-back element, and the configuration of the L-shaped added element. By optimizing these parameters, the antenna achieves resonance at both 2.4 GHz and 5 GHz frequencies, overcoming the fixed frequency relationship (f0 and 3f0) of conventional monopole antennas.
3Device complexity
If a conventional monopole antenna structure is used, then the structure is simpler than parallel two-line antenna, but the antenna cannot provide necessary resonance frequencies for both IEEE 802.11b/g and IEEE 802.11a standards
Solution Approach 1:
The antenna structure is designed to perform multiple functions: the pole element provides resonance for 2.4 GHz band (IEEE 802.11b/g), while the L-shaped folded-back element provides resonance for 5 GHz band (IEEE 802.11a). This multi-functionality allows a single antenna structure to support both wireless LAN standards, achieving universality without requiring separate antennas for each frequency band.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The multiband antenna achieves resonance in both the 2.4 GHz and 5 GHz bands, providing stable communication performance and a widened bandwidth, even when the antenna is held in a hand, with minimal impact on communication performance.
Implementation Method 1
the antenna element section includes a pole element which includes the feeding point, and has a length at which the pole element resonates at a first frequency; an L-shaped folded-back element which is connected to an end of the pole element, and resonates at a second frequency together with the pole element
Data Source
Figure 1A~1C
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AI summary
Disclosed is a multiband antenna, comprising: an antenna element section which is fed from a feeding point; and a ground element section which is connected to a ground of the feeding point; wherein the antenna element section includes: a pole element which includes the feeding point, and has a length at which the pole element resonates at a first frequency; an L-shaped folded-back element which is connected to an end of the pole element, and resonates at a second frequency together with the pole element; and an L-shaped added element which is connected to the pole element; wherein a length from the feeding point to an end of the added element is a length at which the added element resonates at the first frequency.